CHICAGO (CBS) — Approximately 45,000 patients at Rush hospitals in the Chicago area had personal information exposed — including Social Security numbers — in a data breach in January.

In its most recent quarterly report, Rush System for Health revealed it learned on Jan. 22 that an employee of a third-party claims processing vendor had provided someone with unauthorized access to a file containing information on about 45,000 patients.

The data in the file included names, addresses, Social Security numbers, birthdates and health insurance information. The file did not contain medical information, or details on treatment.

Rush said it suspended its contract with the vendor and has taken steps to prevent another data breach in the future.

“Although Rush is not aware of any misuse of any information arising out of this incident, we are providing notice of the incident to all potentially affected individuals as well as providing notice to the Department of Health and Human Services Office of Civil Rights and applicable state regulators, as required by law,” Rush officials stated in their quarterly report.

Rush System for Health operates Rush University Medical Center in Chicago, Rush Copley Medical Center in Aurora, Rush Oak Park Hospital and several clinics and satellite facilities in the Chicago area